Deformarea tuburilor din polietilenă (PE) în procesul de exploatare

Abstract

The article describes a case study that took place during the construction of a Polyethylene pipe adduction with a nominal pressure of 6 to 12.5 bar, due to uneven terrain. After the completion of the work and the positive hydraulic tests, the intake remained filled with water, at a pressure below the working one. Until it was put into operation, it was discovered that the intake was without water and on one section the pipe was deformed. Deformation occurred due to intake/leakage/emptying of water from the pipe in the absence of air access through the vent valve at point CA 5, the highest point of the pipe, where the absolute pressure dropped to values close to zero. In order to determine the possibilities of restoring the deformed pipe, laboratory tests were carried out on samples of Polyethylene pipes with a length of 3.0 m having SDR 26 PN 6 values with diameters between 110 mm and 160 mm, which at the first stage were subjected to mechanical deformations, and in the second stage, they were subjected to hydraulic loads. As a result of tests of Dn 110 tubes; Mr. 125; Dn160 mm at the test pressure values from 0 bar, up to the maximum admissible value of the working pressure of 6 bar, with the interval of 1 bar, with each time measuring the dimensions of the tube in the deformation zone at the temperature above 130C showed that they can be restored.